package main

import (
	"fmt"
	"sync"
)

var wg sync.WaitGroup

func main() {
	ch1 := make(chan int, 1)
	ch1 <- 10
	close(ch1) // 10 true
	x, ok := <-ch1
	fmt.Println(x, ok)
	y, ok := <-ch1
	fmt.Println(y, ok) // 0 false
}
